Lua编程示例（五）： C语言对Lua表的读取和添加

#include "stdafx.h"

lua_state *l;


void load_lua(char *filename){
 l=lual_newstate();
 lual_openlibs(l);
 if((lual_loadfile(l,filename) || lua_pcall(l,0,0,0))!= 0){
 lual_error(l,"loadfile error! \n %s",lua_tostring(l,-1));
 }
}

double getfield(lua_state *l,char * key){
 double res;
 //默认栈顶是table，将key入栈
 lua_pushstring(l,key);
 lua_gettable(l,-2);  //查找键值为key的元素，置于栈顶
 if(!lua_isnumber(l,-1)){
 lual_error(l,"num get error! %s\n",lua_tostring(l,-1));
 }
 res = lua_tonumber(l,-1);
 lua_pop(l,1); //删掉产生的查找结果
 return res;
}
void setfield(lua_state *l,char *key,double value){
 //默认栈顶是table
 lua_pushstring(l,key);
 lua_pushnumber(l,value);
 lua_settable(l,-3); //将这一对键值设成元素
}

struct mycolor{
 char *name;
 unsigned char red,green,blue;
}color[]={
 {"wieth",1,1,1},
 {"black",0,0,0},
 {"blue",0,0,1}
};
//先创建一个空的栈，填入元素，用lua_setglobal弹出表，并赋成全局变量
void setcolor(lua_state *l,struct mycolor col){
 lua_newtable(l);
 setfield(l,"r",col.red);
 setfield(l,"g",col.green);
 setfield(l,"b",col.blue);
 lua_setglobal(l,col.name);
}

void getcolor(lua_state *l,char *key){
 lua_getglobal(l,key);
 if(!lua_istable(l,-1)){
 lual_error(l,"'background' is not a table! %s\n",lua_tostring(l,-1));
 }
 double red;
 double green;
 double blue; 
 red = getfield(l,"r");
 blue = getfield(l,"b");
 green = getfield(l,"g");
 printf("the %s color : red = %.2f ,green = %.2f ,blue = %.2f\n",key,red,green,blue);
}

int _tmain(int argc, _tchar* argv[])
{
 load_lua("test.lua");
 getcolor(l,"background");
 int i = 0;
 while(color[i].name != null){
 setcolor(l,color[i]);
 i++;
 }
 getcolor(l,"wieth");
 getcolor(l,"blue");
 return 0;
}

test.lua 中就一行代码：

background = {r=1,g=0.5,b=0.7} 

运行输出结果为：

the background color : red = 1.00 ,green = 0.50 ,blue = 0.70
the wieth color : red = 1.00 ,green = 1.00 ,blue = 1.00
the blue color : red = 0.00 ,green = 0.00 ,blue = 1.00